The following abbreviations are herewith expanded, at least some of which are referred to within the following description of the state-of-the-art and the present invention.                ASE Amplified Spontaneous Emission        CO Central Office        GPON Gigabit PON        EDFA Erbium-Doped Fiber Amplifier        IEEE Institute of Electrical and Electronics Engineers        OLT Optical Line Terminal        ONT Optical Network Terminal        ONU Optical Network Unit        PON Passive Optical Network        WDM Wavelength Division Multiplexor/demultiplexor        WM Wavelength Multiplexing/demultiplexing module        
An optical network, for example, a PON (passive optical network) may be used as an access network, connecting individual subscribers or groups of subscribers to a core telecommunications network. A typical PON includes, among other components, an OLT (optical line terminal) in a CO (central office) and a number of ONUs (optical network units) at subscriber premises (or some intermediate location). Many residential houses, for example, have an ONU that communicates with an OLT over a FTTH (fiber to the home) PON access network. The network may make available to the subscriber services such as Internet access, telephone, and television. Other optical network may be similarly configured such as that a management node such as an OLT may communicate with multiple end devices, for example in a data center.
As the management node is typically located in a central office or other well-equipped facility, amplification of downstream transmissions (toward the end devices) is handled at the point of transmission. This capability may not always be present in the end devices such as ONUs for cost reasons or to reduce end-device energy consumption. In this case it may be desirable to amplify received upstream signals prior to their normal processing by the management node.
Note that the techniques or schemes described herein as existing or possible are presented as background for the present invention, but no admission is made thereby that these techniques and schemes were heretofore commercialized or known to others besides the inventors. These needs and other needs are discussed further and addressed by the description.